\(\langle \) 7\(\rangle \)  \((S_M^+({\omega }),S_M^-({\omega }))=(0,0)\)  for \(M=N_2({\omega },b)\) 
being trivial (cf. Definition 1.8.11 on p.41 of [1]}) with
\({\omega }=e^{\sqrt{-1}{\theta }}\in {\bf U}\backslash {\bf R}\) .
